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Since FMOD was associated with prechondrocytic mesenchymal cells in the interzone before joint cavitation and with developing articular chondrocytes in the maturing and young adult limbs, it has been proposed that FMOD may function in the early genesis of articular cartilage ([36]). Meanwhile, degradation of FMOD core protein was also observed in interleukin (IL)-1-challenged cartilage ([45]; [44]) - a representative model that elucidates the genetic and molecular pathogenesis of inflammation-related secondary OA ([22]). I In vitro i digestion of healthy human knee cartilage with MMP-13, ADAMTS-4, and ADAMTS-5 generated FMOD fragments of similar sizes as FMOD derived from OA cartilage without digestion ([44]). As aforementioned, FMOD is a critical ECM component involved in articular cartilage development, growth, aging, and arthritis; however, the exact functions of FMOD during arthritis are still unclear. [Extracted from the article]

Morquio A disease (Mucopolysaccharidosis type IVA, MPS IVA) is one of the 11 mucopolysaccharidoses (MPSs), a heterogeneous group of inherited lysosomal storage disorders (LSDs) caused by deficiency in enzymes need to degrade glycosaminoglycans (GAGs). Morquio A is characterized by a decrease in N-acetylgalactosamine-6-sulfatase activity and subsequent accumulation of keratan sulfate and chondroitin 6-sulfate in cells and body fluids. As the pathophysiology of this LSD is not completely understood and considering the previous results of our group concerning oxidative stress in Morquio A patients receiving enzyme replacement therapy (ERT), the aim of this study was to investigate oxidative stress parameters in Morquio A patients at diagnosis. It was studied 15 untreated Morquio A patients, compared with healthy individuals. The affected individuals presented higher lipid peroxidation, assessed by urinary 15-F2t-isoprostane levels and no protein damage, determined by sulfhydryl groups in plasma and di-tyrosine levels in urine. Furthermore, Morquio A patients showed DNA oxidative damage in both pyrimidines and purines bases, being the DNA damage positively correlated with lipid peroxidation. In relation to antioxidant defenses, affected patients presented higher levels of reduced glutathione (GSH) and increased activity of glutathione peroxidase (GPx), while superoxide dismutase (SOD) and glutathione reductase (GR) activities were similar to controls. Our findings indicate that Morquio A patients present at diagnosis redox imbalance and oxidative damage to lipids and DNA, reinforcing the idea about the importance of antioxidant therapy as adjuvant to ERT, in this disorder.

Mucopolysaccharidoses (MPS) screening is tedious and still performed by analysis of total glycosaminoglycans (GAG) using 1,9-dimethylmethylene blue (DMB) photometric assay, although false positive and negative tests have been reported. Analysis of differentiated GAGs have been pursued classically by gel electrophoresis or more recently by quantitative LC-MS assays. Secondary elevations of GAGs have been reported in urinary tract infections (UTI). In this manuscript, we describe the diagnostic accuracy of urinary GAG measurements by LC-MS for MPS typing in 68 untreated MPS and mucolipidosis (ML) patients, 183 controls and 153 UTI samples. We report age-dependent reference values and cut-offs for chondroitin sulfate (CS), dermatan sulfate (DS), heparan sulfate (HS) and keratan sulfate (KS) and specific GAG ratios. The use of HS/DS ratio in combination to GAG concentrations normalized to creatinine improves the diagnostic accuracy in MPS type I, II, VI and VII. In total 15 samples classified to the wrong MPS type could be correctly assigned using HS/DS ratio. Increased KS/HS ratio in addition to increased KS improves discrimination of MPS type IV by excluding false positives. Some samples of UTI patients showed elevation of specific GAGs, mainly CS, KS and KS/HS ratio and could be misclassified as MPS type IV. Finally, DMB photometric assay performed in MPS and ML samples reveal four false negative tests (sensitivity of 94%). In conclusion, specific GAG ratios in complement to quantitative GAG values obtained by LC-MS enhance discrimination of MPS types. Exclusion of patients with UTI improve diagnostic accuracy in MPS IV but not in other types., Competing Interests: Déborah Mathis, Jean‐Christophe Prost, Gabriela Mäder, Liya Arackal, Haoyue Zhang, Sandra Kurth, Katrin Freiburghaus, and Jean‐Marc Nuoffer declare that they have no conflict of interest., (© 2024 The Authors. JIMD Reports published by John Wiley & Sons Ltd on behalf of SSIEM.)

We developed two human-induced pluripotent stem cell (hiPSC)/human embryonic stem cell (hESC)-specific glycan-recognizing mouse antibodies, R-10G and R-17F, using the Tic (JCRB1331) hiPSC line as an antigen. R-10G recognizes a low-sulfate keratan sulfate, and R-17F recognizes lacto-N-fucopentaose-1. To evaluate the general characteristics of stem cell glycans, we investigated the hiPSC line 201B7 (HPS0063), a prototype iPSC line. Using an R-10G affinity column, an R-10G-binding protein was isolated from 201B7 cells. The protein yielded a single but very broad band from 480 to 1236 kDa by blue native gel electrophoresis. After trypsin digestion, the protein was identified as podocalyxin by liquid chromatography/mass spectrometry. According to Western blotting, the protein reacted with R-10G and R-17F. The R-10G-positive band was resistant to digestion with glycan-degrading enzymes, including peptide N-glycanase, but the intensity of the band was decreased significantly by digestion with keratanase, keratanase II, and endo-β-galactosidase, suggesting the R-10G epitope to be a keratan sulfate. These results suggest that keratan sulfate-type epitopes are shared by hiPSCs. However, the keratan sulfate from 201B7 cells contained a polylactosamine disaccharide unit (Galβ1-4GlcNAc) at a significant frequency, whereas that from Tic cells consisted mostly of keratan sulfate disaccharide units (Galβ1-4GlcNAc(6S)). In addition, the abundance of the R-10G epitope was significantly lower in 201B7 cells than in Tic cells.

Introduction: Oral supplementation of chondroitin sulfate (CS) and glucosamine (GlcN), symptomatic slow-acting molecules, is recommended by European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis and Musculoskeletal Diseases (ESCEO) and other European Union (EU) guidelines for the restoration of the articular cartilage surface in patients affected by osteoarthritis (OA). They are commercialized as pharmaceutical grade products and as food supplements in combination with plant extracts hyaluronic acid, methylsulfonylmethane, and other components. Food supplements do not need to undergo the strict regulatory controls of pharmaceutical grade products; thus, composition and contaminants that could be present may not be evidenced before commercialization and these uncertainties may give rise to concerns about the bioactivity of these formulations.Methods: In this paper 10 different food supplements (FS) from diverse European countries were analyzed in comparison with two pharmaceutical grade products (Ph) using updated analytical approaches and biochemical cell-based assays. The purity, the titer, and the origin of CS in Ph and FS samples were initially assessed in order to successively compare the biological function. Both food supplements and pharmaceutical formulations were tested in vitro, using the same final CS concentration, on primary chondrocytes and synoviocytes in terms of (i) cell viability, (ii) activation of the NF-κB-mediated inflammation pathway, (iii) cartilage oligomeric matrix protein (COMP-2), IL-6, and IL-8 production.Results: All the FS presented a certain insoluble fraction; the CS and the GlcN contents were lower than the declared ones in 9/10 and 8/10 samples, respectively. All FS contained keratan sulfate (KS) at up to 50% of the total glycosaminoglycan amount declared on the label. Primary cells treated with the samples diluted to present the same CS concentration in the medium showed cytotoxicity in 7/10 FS while Ph preserved viability and reduced NF-κB, COMP-2, and secreted inflammatory cytokines.Conclusion: Among all samples tested, the pharmaceutical grade products demonstrated effective modulation of biomarkers counteracting the inflammation status and improving viability and the physiological condition of OA human primary chondrocyte and synoviocyte cells. In contrast to that, most FS were cytotoxic at the tested concentrations, and only 3/10 of them showed similarities to Ph sample behavior in vitro.Funding: This work was partially supported by PON01_1226 NUTRAFAST, MIUR Ministero dell'Università e della Ricerca Scientifica. Bioteknet financed two short-term grants for graduate technicians. The journal's Rapid Service and Open Access fees were funded by IBSA CH. [ABSTRACT FROM AUTHOR]

Glycosaminoglycans (GAG) from the velvet antlers of Sika deer (Cervus nippon) at the different growing stages (Fukurozuno, Anshi, and Santajo) of bred and wild deer were isolated and their concentrations and sulfation patterns were analyzed. GAG were digested with chondroitinase ABC, ACI, heparinase-I and -III, and keratanase-II into the corresponding repeating disaccharides of chondroitin sulfate (CS), dermatan sulfate (DS), hyaluronan, heparan sulfate (HS), and keratan sulfate. Cartilaginous tissues contained CS-DS at high concentrations with an almost equal ratio of 4- and 6-sulfates, while 4-sulfate-type CS-DS predominantly occupied ossified tissues, but at low concentrations. High O- and N-sulfation degrees of HS correspond to high ossification. Dynamic quantitative changes in CS-DS and compositional changes in CS-DS and HS were closely associated with the mineralization of deer antlers. [ABSTRACT FROM AUTHOR]

Morquio A syndrome is an autosomal mucopolysaccharide storage disorder that leads to accumulation of keratan sulfate. Diagnosis of this disease can be aided by measuring the levels of keratan sulfate in the urine. This requires the liquid chromatography tandem mass spectrometry (LCMS/MS) measurement of sulfated N‐acetyl‐d‐lactosamines in the urine after cleavage of the keratan sulfate with keratanase II. Quantification requires isotopically‐labelled internal standards. The synthesis of these 13C6‐labelled standards from 13C6‐galactose and N‐acetylglucosamine is described. The required protected disaccharide is prepared utilising a regioselective, high yielding β‐galactosylation of a partially protected glucosamine acceptor and an inverse addition protocol. Subsequent synthesis of the 13C6‐labelled mono and disulfated N‐acetyllactosamines was achieved in five and eight steps, respectively, from this intermediate to provide internal standards for the LCMS/MS quantification of keratan sulfate in urine. Accurate quantification of glycosaminoglycans in a patient's urine aids in the diagnosis of mucopolysaccharidosis diseases. Measuring levels of keratan sulfate requires heavy atom labelled monosulfated and disulfated N‐acetyllactosamines as internal standards for mass spectrometry analysis. The synthesis of these standards from 13C6‐galactose and N‐acetylglucosamine is described and utilises a selective, high yielding glycosylation with a partially protected acceptor via an inverse addition protocol. [ABSTRACT FROM AUTHOR]

Morquio B disease (MBD) is an autosomal recessive GLB1-gene-related lysosomal storage disease, presenting with a peculiar type of dysostosis multiplex which is also observed in GALNS-related Morquio A disease. MBD may present as pure skeletal phenotype (pure MBD) or in combination with the neuronopathic manifestations seen in type 2 (juvenile) or type 3 (late onset) GM1 gangliosidosis (MBD plus). The main skeletal features are progressive growth impairment, kyphoscoliosis, coxa/genua valga, joint laxity, platyspondyly and odontoid hypoplasia. The main neuronopathic features are dystonia, ataxia, and intellectual/developmental/speech delay. Spinal cord compression occurs as a complication of spinal dysostosis. Chronic pain is reported, along with mobility issues and challenges with daily living and self-care activities, as the most common health concern. The most commonly reported orthopedic surgeries are hip and knee replacements. Keratan sulphate-derived oligosaccharides are characteristic biomarkers. Residual β-galactosidase activities measured against synthetic substrates do not correlate with the phenotype. W273 L and T500A are the most frequently observed GLB1 variants in MBD, W273L being invariably associated with pure MBD. Cytokines play a role in joint destruction and pain, providing a promising treatment target. In the future, patients may benefit from small molecule therapies, and gene and enzyme replacement therapies, which are currently being developed for GM1 gangliosidosis.

This study has identified keratan sulfate in fetal and adult rat spinal cord and vertebral connective tissues using the antibody BKS-1(+) which recognizes a reducing terminal N-acetyl glucosamine-6-sulfate neo-epitope exposed by keratanase-I digestion. Labeling patterns were correlated with those of lumican and keratocan using core protein antibodies to these small leucine rich proteoglycan species. BKS-1(+) was not immunolocalized in fetal spinal cord but was apparent in adult cord and was also prominently immunolocalized to the nucleus pulposus and inner annulus fibrosus of the intervertebral disc. Interestingly, BKS-1(+) was also strongly associated with vertebral body ossification centers of the fetal spine. Immunolocalization of lumican and keratocan was faint within the vertebral body rudiments of the fetus and did not correlate with the BKS-1(+) localization indicating that this reactivity was due to another KS-proteoglycan, possibly osteoadherin (osteomodulin) which has known roles in endochondral ossification. Western blotting of adult rat spinal cord and intervertebral discs to identify proteoglycan core protein species decorated with the BKS-1(+) motif confirmed the identity of 37 and 51 kDa BKS-1(+) positive core protein species. Lumican and keratocan contain low sulfation KS-I glycoforms which have neuroregulatory and matrix organizational properties through their growth factor and morphogen interactive profiles and ability to influence neural cell migration. Furthermore, KS has interactive capability with a diverse range of neuroregulatory proteins that promote neural proliferation and direct neural pathway development, illustrating key roles for keratocan and lumican in spinal cord development.

Mucopolysaccharidosis type IVA (MPS IVA, or Morquio syndrome type A) is an inherited metabolic lysosomal disease caused by the deficiency of the N-acetylglucosamine-6-sulfate sulfatase enzyme. The deficiency of this enzyme accumulates the specific glycosaminoglycans (GAG), keratan sulfate, and chondroitin-6-sulfate mainly in bone, cartilage, and its extracellular matrix. GAG accumulation in these lesions leads to unique skeletal dysplasia in MPS IVA patients. Clinical, radiographic, and biochemical tests are needed to complete the diagnosis of MPS IVA since some clinical characteristics in MPS IVA are overlapped with other disorders. Early and accurate diagnosis is vital to optimizing patient management, which provides a better quality of life and prolonged life-time in MPS IVA patients. Currently, enzyme replacement therapy (ERT) and hematopoietic stem cell transplantation (HSCT) are available for patients with MPS IVA. However, ERT and HSCT do not have enough impact on bone and cartilage lesions in patients with MPS IVA. Penetrating the deficient enzyme into an avascular lesion remains an unmet challenge, and several innovative therapies are under development in a preclinical study. In this review article, we comprehensively describe the current diagnosis, treatment, and management for MPS IVA. We also illustrate developing future therapies focused on the improvement of skeletal dysplasia in MPS IVA.

The role of proteoglycans in the central nervous system (CNS) is a rapidly evolving field and has major implications in the field of CNS injury. Chondroitin sulfate proteoglycans (CSPGs) increase in abundance following damage to the spinal cord and inhibit neurite outgrowth. Major advances in understanding the interaction between outgrowing neurites and CSPGs has created a need for more robust and quantitative analyses to further our understanding of this interaction. We report the use of a high-throughput assay to determine the effect of various post-translational modifications of aggrecan upon neurite outgrowth from NS-1 cells (a PC12 cell line derivative). Aggrecan contains chondroitin sulfate, keratan sulfate, and N-linked oligosaccharides (N-glycans), each susceptible to removal through different enzymatic digestions. Using a sequential digestion approach, we found that chondroitin sulfate and N-glycans, but not keratan sulfate, contribute to inhibition of neurite outgrowth by substrate-bound aggrecan. For the first time, we have shown that N-linked oligosaccharides on aggrecan contribute to its inhibition of neuritogenesis.

Highlights • A glycosaminoglycan, keratan sulfate, may be involved in COPD development. • Keratan sulfate disaccharide L4 has anti-inflammatory activity and suppresses COPD. • Langerin is a potential L4 receptor. • L4 oligomers show over 1000-fold higher affinity toward langerin than the L4 monomer. Abstract Glycosylation is profoundly involved in various diseases, and interactions between glycan binding proteins and their sugar ligands are plausible drug targets. Keratan sulfate (KS), a glycosaminoglycan, is downregulated in lungs by cigarette smoking, suggesting that KS is involved in smoking-related diseases, such as chronic obstructive pulmonary disease (COPD). We found that a highly sulfated KS disaccharide, L4, suppresses lung inflammation and is effective against COPD and its exacerbation in mouse models. Its anti-inflammatory activity was comparable to that of a steroid. As a possible mechanism, langerin, a C-type lectin receptor (CLR) expressed in dendritic cells, was suggested to function as an L4 receptor. Oligomeric L4 derivatives were chemically designed to create new ligands with higher affinity and activity. The synthetic L4 oligomers bound to langerin with over 1000-fold higher affinity than the L4 monomer, suggesting that these compounds are effective drug candidates against COPD and inflammatory diseases. [ABSTRACT FROM AUTHOR]

Keratan sulfate possesses considerable amounts of negatively charged sulfonic acid groups and participates in biomineralization. In the present study, we investigated characteristics and functions of a CHST1 gene identified from the pearl oyster Pinctada fucata martensii ( PmCHST1b ) which participated in the synthesis of keratan sulfate. PmCHST1b amino acid sequence carried a typical sulfotransferase-3 domain (sulfotransfer-3 domain) and belonged to membrane-associated sulfotransferases. Homologous analysis of CHST1 from different species showed the conserved motif (5′ PSB motif and 3′ PB motif) which interacted with 3′-phosphoadenosine-5′-phosphosulfate (PAPS). Structure analysis of sulfotransferase domain indicted that PmCHST1b showed the conserved catalytic structure character and the relationships presented in the phylogenetic tree conformed to that of traditional taxonomy. Expression pattern of PmCHST1b in different tissues and development stages showed that PmCHST1b widely expressed in all the detected tissues and development stages and showed the highest expression level in the central zone of mantle (MC). PmCHST1b expressed highly in the trochophore, D-stage larvae and spat which corresponded to prodissoconch and dissoconch shell formation, respectively. RNA interference (RNAi) successfully inhibited expression level of PmCHST1b in MC ( P <0.05), and sulfate polymer content in the extrapallial fluid significantly reduced ( P <0.05). Crystallization of shell nacre became irregular. Results above indicated that PmCHST1b may affect nacre formation by participating in synthesis of keratan sulfate in extrapallial fluid. This study provided fundamental materials for further research on the role of sulfotransferases and keratan sulfate in nacre formation. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to use the liquid chromatography/tandem mass spectrometry (LC‐MS/MS) method to quantitate levels of three urinary glycosaminoglycans (GAGs; dermatan sulfate [DS], heparan sulfate [HS], and keratan sulfate [KS]) to help make a correct diagnosis of mucopolysaccharidosis (MPS). Methods: We analyzed the relationships between phenotypes and levels of urinary GAGs of 79 patients with different types of MPS. Results: The patients with mental retardation (n = 21) had significantly higher levels of HS than those without mental retardation (n = 58; 328.8 vs. 3.2 μg/ml, p < 0.001). The DS levels in the patients with hernia, hepatosplenomegaly, claw hands, coarse face, valvular heart disease, and joint stiffness were higher than those without. Twenty patients received enzyme replacement therapy (ERT) for 1–12.3 years. After ERT, the KS level decreased by 90% in the patients with MPS IVA compared to a 31% decrease in the change of dimethylmethylene blue (DMB) ratio. The DS level decreased by 79% after ERT in the patients with MPS VI compared to a 66% decrease in the change of DMB ratio. Conclusions: The measurement of GAG fractionation biomarkers using the LC‐MS/MS method is a more sensitive and reliable tool than the DMB ratio for MPS high‐risk screening, diagnosis, subclass identification, and monitoring the efficacy of ERT. The measurement of GAG fractionation biomarkers using the LC‐MS/MS method is a more sensitive and reliable tool than the DMB ratio for MPS high‐risk screening, diagnosis, subclass identification, and monitoring the efficacy of ERT. [ABSTRACT FROM AUTHOR]

Abstract Mucopolysaccharidosis IVA (MPS IVA, Morquio A syndrome) is an autosomal recessive disorder caused by the deficiency of N -acetylgalactosamine-6-sulfate sulfatase. Deficiency of this enzyme leads to the accumulation of specific glycosaminoglycans (GAGs), chondroitin-6-sulfate (C6S) and keratan sulfate (KS), which are mainly synthesized in the cartilage. Therefore, the substrates are stored primarily in the cartilage and its extracellular matrix (ECM), leading to a direct impact on bone development and successive systemic skeletal spondylepiphyseal dysplasia. The skeletal-related symptoms for MPS IVA include short stature with short neck and trunk, odontoid hypoplasia, spinal cord compression, tracheal obstruction, obstructive airway, pectus carinatum, restrictive lung, kyphoscoliosis, platyspondyly, coxa valga, genu valgum, waddling gait, and laxity of joints. The degree of imbalance of growth in bone and other organs and tissues largely contributes to unique skeletal dysplasia and clinical severity. Diagnosis of MPS IVA needs clinical, radiographic, and laboratory testing to make a complete conclusion. To diagnose MPS IVA, total urinary GAG analysis which has been used is problematic since the values overlap with those in age-matched controls. Currently, urinary and blood KS and C6S, the enzyme activity of GALNS, and GALNS molecular analysis are used for diagnosis and prognosis of clinical phenotype in MPS IVA. MPS IVA can be diagnosed with unique characters although this disorder relates closely to other disorders in some characteristics. In this review article, we comprehensively describe clinical, radiographic, biochemical, and molecular diagnosis and clinical assessment tests for MPS IVA. We also compare MPS IVA to other closely related disorders to differentiate MPS IVA. Overall, imbalance of growth in MPS IVA patients underlies unique skeletal manifestations leading to a critical indicator for diagnosis. Highlights • Mucopolysaccharidosis IVA is an autosomal recessive disorder caused by the deficiency of GALNS. • This enzyme deficiency leads to a progressive accumulation of excessive C6S and KS. • Spinal cord compression, airway compromise, and valvular heart disease are the leading cause of morbidity and mortality. • Attenuated form may not be evident until late childhood or adolescence, and first manifests as hip problems. • Imbalance of growth in bones, organs, and tissues causes the hallmark of clinical manifestations. [ABSTRACT FROM AUTHOR]

Abstract To explore the correlation between glycosaminoglycan (GAG) levels and mucopolysaccharidosis (MPS) type, we have evaluated the GAG levels in blood of MPS II, III, IVA, and IVB and urine of MPS IVA, IVB, and VI by tandem mass spectrometry. Dermatan sulfate (DS), heparan sulfate (HS), keratan sulfate (KS; mono-sulfated KS, di-sulfated KS), and the ratio of di-sulfated KS in total KS were measured. Patients with untreated MPS II had higher levels of DS and HS in blood while untreated MPS III had higher levels of HS in blood than age-matched controls. Untreated MPS IVA had higher levels of KS in blood and urine than age-matched controls. The ratio of blood di-sulfated KS/total KS in untreated MPS IVA was constant and higher than that in controls for children up to 10 years of age. The ratio of urine di-sulfated KS/total KS in untreated MPS IVA was also higher than that in age-matched controls, but the ratio in untreated MPS IVB was lower than controls. ERT reduced blood DS and HS in MPS II, and urine KS in MPS IVA patients, although GAGs levels remained higher than the observed in age-matched controls. ERT did not change blood KS levels in MPS IVA. MPS VI under ERT still had an elevation of urine DS level compared to age-matched controls. There was a positive correlation between blood and urine KS in untreated MPS IVA patients but not in MPS IVA patients treated with ERT. Blood and urine KS levels were secondarily elevated in MPS II and VI, respectively. Overall, measurement of GAG levels in blood and urine is useful for diagnosis of MPS, while urine KS is not a useful biomarker for monitoring therapeutic efficacy in MPS IVA. Highlights • ERT for MPS II, IVA, and VI does not normalize GAG levels. • MPS IVA and IVB are distinguishable by assaying blood and urine KS. • Positive correlation between blood and urine mono- and di-sulfated KS in untreated MPS IVA samples is present. • Negative correlation between blood and urine levels of mono- and di-sulfated KS in ERT treated MPS IVA is present. • Urine KS is valuable for diagnosis of MPS IVA but not for monitoring therapeutic effect of ERT [ABSTRACT FROM AUTHOR]

Background Langerin, a C-type lectin receptor (CLR) expressed in a subset of dendritic cells (DCs), binds to glycan ligands for pathogen capture and clearance. Previous studies revealed that langerin has an unusual binding affinity toward 6-sulfated galactose (Gal), a structure primarily found in keratan sulfate (KS). However, details and biological outcomes of this interaction have not been characterized. Based on a recent discovery that the disaccharide L4, a KS component that contains 6-sulfo-Gal, exhibits anti-inflammatory activity in mouse lung, we hypothesized that L4-related compounds are useful tools for characterizing the langerin-ligand interactions and their therapeutic application. Methods We performed binding analysis between purified long and short forms of langerin and a series of KS disaccharide components. We also chemically synthesized oligomeric derivatives of L4 to develop a new high-affinity ligand of langerin. Results We show that the binding critically requires the 6-sulfation of Gal and that the long form of langerin displays higher affinity than the short form. The synthesized trimeric (also designated as triangle or Tri) and polymeric (pendant) L4 derivatives displayed over 1000-fold higher affinity toward langerin than monomeric L4. The pendant L4, but not the L4 monomer, was found to effectively transduce langerin signaling in a model cell system. Conclusions L4 is a specific ligand for langerin. Oligomerization of L4 unit increased the affinity toward langerin. General significance These results suggest that oligomeric L4 derivatives will be useful for clarifying the langerin functions and for the development of new glycan-based anti-inflammatory drugs. [ABSTRACT FROM AUTHOR]